This invention relates to ring binding mechanisms and, more particularly, to the heavy duty ring binding mechanisms for sheet materials such as paper and the like.
Heavy duty ring binders used for photo albums, parts catalogs, salesmen presentation kits, student notes and classroom materials, office records and the like typically include a plurality of generally O-, U- or D- shaped metal rings for holding apertured sheets of paper or the like. These rings divide in half to open and are opened individually or together to remove, replace or add sheets. With minimum use, the area around the holes of the sheets become torn from the misaligned and jagged ends of these rings. Consequently, for many applications the area of the sheets surrounding the holes must be reinforced.
Conventional heavy duty binders have a number of other shortcomings. Assembly costs represent a large percentage of the total cost of production, up to as much as 50% or more in some cases. Empty binders occupy a substantial amount of unusable space, making it uneconomical to transport them for any distance more than a few hundred miles and requiring unnecessarily large storage spaces for inventories maintained by retailers or companies using a large number of binders. The covers of some binders are colored and/or permanently decorated and usually are discarded when it becomes necessary to change the color or the identification on the cover.